1. Field
Exemplary embodiments relate to an image forming apparatus and a power control method thereof, and more particularly, to an image forming apparatus, power of which is controlled by turning on/off direct current (DC) power of a secondary circuit, and a power control method thereof.
2. Description of the Related Art
An image forming apparatus forms an image to be printed on a printing medium. The image forming apparatus may be embodied in a printer, a copy machine, a facsimile, a multi-function peripheral having two or more functions, etc.
For power control of the image forming apparatus, there may be used a method of preparing a mechanical switch at one side of the image forming apparatus and completely shutting off operating power supplied for operation.
However, in the case where a method of turning on/off alternating current (AC) power of a primary circuit is used, an AC harness of a power inlet generally placed in a back side of the image forming apparatus has to be connected to a front side in order to place the switch in a front side of the image forming apparatus for a user's convenience in operating the switch. This causes problems in designing the apparatus and increases production costs.
Also, because the mechanical switch is turned on/off by a user regardless of operations such a printing, data transmission/reception, data storage, etc. of the image forming apparatus, damage may occur. For example, if the switch is turned off while the printing or the like job is performed, data may be abnormally (improperly or incorrectly) backed up and thus lost, or a logic circuit or the like inner parts of the image forming apparatus may be damaged.
Thus, there may be employed a method of controlling the DC power through a secondary circuit provided with a small capacity switching device such as a transistor (e.g., field effect transistor (FET).
Since the above method of switching on/off the DC power of the secondary circuit uses the small capacity device, it is possible to keep a standby power of 1 watt (1 W) or less in an off status. Thus, the data backup is normally achieved even when the switch is turned off, thereby preventing the data from loss or the parts from damage. Accordingly, the method of switching on/off the DC power of the secondary circuit has widely spread. Further, both the primary circuit and the secondary circuit may be used.
Although it is possible to protect data from loss due to the power switch off through the method of turning on/off the secondary circuit, there is still a problem in that data may be lost because the data backup operation is not implemented in the case of unexpected power-off such as a power failure.
Also, when power supplying is resumed after the unexpected (abnormal) power-off due to the power failure, switch operation of the primary circuit, etc. is terminated, and the image forming apparatus is forcibly turned on or off on the basis of preset information since it has no information about a previous power status.
Accordingly, if the image forming apparatus is previously set up to be turned on, power is supplied to the image forming apparatus and thus wastefully consumed. On the other hand, if the image forming apparatus is previously set up to be turned off, printing data received before the unexpected power-off and being on standby, fax data being received, or the like may be lost and it is thus inconvenient for a user.
For the convenience in power control, an additional microcomputer (MICOM) may be used, but the use of the MICOM costs a great deal.